edfishjr

I asked my tire guy if he had any trouble mounting? He said "They're all kinda hard these days, but it was nothin' special or my guys would have come bitch at me." (I didn't have them heat-cycled.)

Tonight I took out the aftermarket Alpine amp and replaced the aftermarket AGM battery with a standard 2-year one from Walmart. The price was a shocker: $110. (If it fails quick I'll just get another one, for free.) That removed 15.7lb of excess weight in total, weight that wouldn't be there in a stock car. There's another legal battery, a Diehard Silver, for $194, that would be even lighter, but something weird is going on. They cannot be ordered. There are 432 of them sequestered in a warehouse in Nashville that they won't let out into the wild. Probably a bad batch.

I got the new front bumpstops in a couple days ago. Big difference. Front end really bites hard and fast now with much less roll, which is what I was after.
Rears arrive tomorrow. Compressing the wacky springs to disassemble the strut is a real PITA. I'll certainly get really good at it before this is done.

The front feels so good I'm now pretty convinced I'll go with a multi-adjustable rear bar to tune balance at events. Bespoke-valved struts will be last.

Next event this Saturday.

oofie810

Is the effort/work involved to change bumpstops similar to the effort/work involved when changing shock absorbers?

Watching his thread closely as I have a 987.2 base with stock everything which I've been running as is with 245/275 re71 on same wheels as you. Looking to see how you develop the car and maybe I can base my changes on what you do.

edfishjr

Yes. You remove the strut from the car, then remove the spring from the strut. Swap out the bump stop(s), put it all back together, check your alignment. I was doing rotors and pads at the same time in the front.

Determining what number, type, stiffness bumpstops to use and balance front and rear is the engineering & testing part. They have to have the hole enlarged to fit the large diameter shaft of the strut which is larger than any shock absorber. I made a clamping tool to facilitate drilling. The ones I'm using in the rear must be thinned to meet the height requirement. There are some one-piece "strut" bumpstops from Bilstein like what the car comes with that may be stiffer than stock and require no mods. They would be helpful and easier, but none are stiff enough nor as linear as I wanted.

What I have learned for sure is that you never want to drive a Cayman/Boxster/Carrera with deteriorated bumpstops, much less autocross one. I don't know what their usable life is but it sure isn't 15 years.

Once I get a tested, working configuration that produces good results (if I ever do) then I'll probably publish the details.

edfishjr

2nd Event:
-In the middle of the first run I knew that the car will be competitive in CS
-Bumpstops made a huge difference. More oversteer, more grip, less roll. Easy to handle. Very bouncy now since the shocks can't keep up.
-I was 2nd of 11 in CS and 7th pax overall. Huge move up.

I think I was a little conservative on the bumpstops. Now plan to go up one durometer step and add an adjustable front bar.

arthurc604

Encouraging result! My Cayman S is looking at me nervously.

arthurc604

Do you have a gut feeling for how much benefit (if any) there would be with a 10mm lower PASM-equipped car/unicorn? I know Brandon Porambo did pretty well in BS with his non-PASM car so <shrug>.

BmacIL

Was the base available with PASM?

On the S it's not an option you want to skip, being both lower and firmer rates. I'd have to check but I think the sway bars are different with PASM too. Edit - true only for the Boxster, not the Cayman.

Brandon's car had PASM. I chatted with him on his setup after 2022 Nats.

arthurc604

Hrm... in his reply to my comment he indicated that he did not have PASM:
This car has PASM so I presume it could have been optioned. You can also find base models optioned with the 6-speed. https://bringatrailer.com/listing/20...che-cayman-74/

BmacIL

🤷🏻‍♂️

arthurc604

LOL, maybe he wants to keep us all guessing.

BmacIL

Such a low take rate but it's there, look at that.
Buy PASM springs, run Bilsteins or Konis 👍

arthurc604

Don't think that would be Street class legal unless you can manage to retrofit everything related to the PASM option.

BmacIL

You can put in the button and controller and have them non-functional. Similar putting 100% passive dampers on a PASM car - just program it out and disconnect & tie up the harnesses. As long as the shocks meet the requirements in the rules for OAL and travel, along with the stops.

arthurc604

My view is that I would not protest another competitor who performed a retrofit in that manner, but if I had responsibility to decide on a protest brought before me, I'd want to see documentation proving all of the parts necessary for a PASM retrofit which I think will be a pretty tough ask.

BmacIL

It's complicated. Shock changes are allowed. Option package conversions are allowed. Sequentially following adding the whole option pack and then taking it all apart to swap the core allowed part can definitely be done, but adds needless cost.

It reminds me of the performance package for the 2015+ Mustang GTs. There are real suspension and brake differences that make a difference and can be swapped. But be worried that someone might protest you for not having the physical oil pressure and MAF gauges in the middle of the instrument panel that offer no performance benefit.